Tips/tricks on Replacing an Impeller?

[Gopher]

I'm going to replace the impeller on my 75 hp Merc tiller. It's on its 7th season and I haven't repalced it so I'm way overdue. I found Surface Tension's post from Oct '04. I'm not the most mechanically inclined person, but I think I can do it. Any other tips/tricks? Will I need RTV silicone or gasket sealant? How much torque should I use when reattaching the lower unit?

From Suface Tension (Thank you):

Put the engine in gear then remove the prop.

Remove the nuts from the lower unit, you'll find them in the area of the cavitation plate. Now look for a plastic plug on the rear of the lower unit, its directly above the trim fin, remove the bolt and the fin should come off and the lower unit should drop but you might have to do coax it along. Don't pry between lower unit and the drive with anything. If it doesn't pull off then you or I are missing a nut or bolt that needs to be removed. I don't think you need to disconnect any shift linkage with that motor but thats just one more reason to have a manual for reference.

Once the lower unit is out you'll notice the drive shaft and a water tube{usually copper} At the base of the drive shaft is the water pump housing, take the top cover off carefully without damaging the gasket or o-ring. Under the cover is the impeller. Slide the impeller off the drive shaft. Note the direction the fins are spun, I've heard it doesn't matter which direction the fin are pointed with the new impeller because once the motor turns over they take their own Right position but I like to line them up.

You'll also have either a pin or a key of some type that keeps the impeller from spinning freely on the drive shaft, don't lose it. While you have the impeller off look for any debris in the water port and it wouldn't hurt to blow them out. Also look at the surfaces inside the water pump housing for burnt on impeller {any other reason why you don't start any outboard with out it being in water} or gouges.

Now replace the impeller while lining up the pin or key.

Replace the top of the housing, if it has a gasket you can use and RTV silicone but don't put it on as to where it could overflow into the water pump.

Time to put the lower unit back on. Align the drive shaft and water tube and slide the lower unit back on, you shouldn't have to use force.

[jwhjr]

I had had no prior experience doing this when I replaced the pump/impeller on my 81 Evinrude, but I found that the instructions that came with the parts was helpful as well.

[Surface Tension]

Gopher, your welcome and glad you can use the info.

I'm not positive on your outboard but Merc uses a slip type joint on the shift linkage so you might luck out there.

Sorry I don't have the torque specs. As with anything like that use a cross pattern when you snug the bolts down then finish up torquing them down. You shouldn't need any sealant there.

[Gopher]

Surface Tension and JWJHR, thanks for your help.

Surface Tension, I see you are in Twig. When i was young I passed through there every weekend on my way to a cabin on Lake Nichols.